The Breathing Diabetic Summary

This study was motivated by other studies (some of which we have reviewed here) that have found that hypoxia lowers blood sugar independent of insulin. However, this study wanted to focus specifically on intermittent exercise because it is often easier than continuous exercise (e.g., 5 min cycles versus 1 hour of continuous exercise). If intermittent exercise in hypoxia provides benefits in glycemic control, it might be a more acceptable, less time-consuming form of exercise treatment for diabetic patients.

The study had 3 groups performing different protocols. One group performed 1-hour of moderate, continuous exercise in hypoxia (O2 ~ 14.7%; well within the therapeutic range). Two other groups performed intermittent exercise of with more intense bouts of effort for 5 min, then 5 min of rest, for 60 min total. One group performed the intermittent exercise in normoxia and the other in hypoxia (O2 ~ 14.7% again).

The authors found that all three protocols lowered blood sugar post-exercise, with the largest improvements coming from the hypoxic continuous exercise. However, insulin levels and insulin resistance were both reduced in the hypoxic exercise programs, whereas they were unchanged in the normoxic group. Further, intermittent exercise in hypoxia improved beta cell function in measurements taken 48 h after the experiment.

Overall, this study found that continuous exercise in hypoxia provided the largest improvements in glycemic control for these type 2 diabetics. However, intermittent exercise in hypoxia also provided glycemic benefits and improved insulin sensitivity and beta cell function.

For us, this is another study supporting the use of intermittent hypoxia for 1) short-term glycemic control and 2) long-term improvements in insulin sensitivity. Obviously, we have to consider hormones and activation of the sympathetic nervous system, but simply doing some easy breath holds during a walk might be sufficient to improve glycemic control.

Conclusion: HyEx60 offered the greatest improvements in acute and moderate-term glucose control in T2D. Intermittent exercise stimulated glucose disposal and improved post-exercise insulin resistance, which was enhanced when exercise was combined with hypoxia (Hy5:5). The data suggest a use of hypoxic exercise in treatment of T2D.